See also Filtrar
Measure CO2, air flow. Count people. Time?
Push vs. pull.
Heights and location.
Specifications to assist manufacturers, buyers, and regulators. Power requirements including not using batteries if it is in high sunlight hours.
Aireamos - how to structure this page? @aireamos guide by testing the available meters. @jljcolorado is a member of aireamos. The guide: Aireamos.org/medidores/